Stomach: Adenocarcinoma

Gastric Polyps

Location

  • Most Common Site: Antrum
  • Fundus
    • Cause: Long Term PPI Use
    • No Malignant Potential

Types

  • Non-Malignant
    • Inflammatory Polyp
    • Hamartomatous Polyp
  • Premalignant
    • Hyperplastic Polyp
      • Most Common (70-90%)
      • Seen in Chronic Atrophic Gastritis
      • Low CA Risk
    • Adenomatous Polyp
      • Highest CA Risk

Treatment

  • < 2 cm or Not Sessile: EGD Polypectomy
    • Can Observe Small Polyps (< 0.5 cm) in Setting of Chronic Inflammation
  • > 2 cm & Sessile: Surgical Resection

Gastric Adenocarcinoma 1

Gastric Adenocarcinoma

Risk Factors

  • H pylori (Most Common)
  • Smoked Meats, Pickled Foods & High Salt
  • Tobacco
  • Blood Type A
  • Chronic Gastritis & Pernicious Anemia
  • Epstein-Barr Virus

Genetic Syndromes

Presentation

  • Sx: Pain, Nausea, Vomiting, Dyspepsia & Anorexia
  • Complications:
    • GI Bleed
    • Gastric Outlet Obstruction – Cancer is the Most Common Cause

Lauren Classification

  • Intestinal Type (Well-Differentiated)
    • Histology: Cells Adhere to Each Other & Arrange with Tubule/Gland Formation
    • Most Common in High-Risk Populations (Elderly Japanese Male)
    • Strongly Associated with H. pylori
    • Better Prognosis
  • Diffuse Type (Poorly-Differentiated)
    • Histology: Lack of Adhesion with Diffuse Lymphatic Invasion
      • No Tubule/Gland Formation
    • Most Common in Low-Risk Populations (Women & Young)
    • More Common in Patients with an Inherited Syndrome
    • Worse Prognosis
    • Linitis Plastica
      • An Aggressive Form with Extensive Submucosal Spread

Special Metastases

  • Sister Mary Joseph Nodule: Met to Umbilicus; Suggests Carcinomatosis
  • Krukenberg Tumor: Met to Ovary
  • Virchow’s Nodes: Met to Supraclavicular Nodes
  • Irish Node: Met to Left Axilla

5-Year Survival

  • Stage I: 88-93.6%
  • Stage II: 68-81.8%
  • Stage III: 17.9-54%
  • Stage IV: 4-5%
    • Median Survival 3-6 Months
    • Up to 1/3 of Patients in the West Stage IV at Diagnosis

Diagnosis

  • Dx: Upper Endoscopy
    • Biopsy for Tissue Diagnosis
    • Endoscopic US – Best Test for T Staging
  • Consider CT or PET-CT to Evaluate Distant Metastases
  • Diagnostic Laparoscopy Indications:
    • Stage ≥ T1b Prior to Gastrectomy or Perioperative Chemoradiation
    • Prior to Preoperative Chemotherapy
    • Presence of GE-Junction Tumor or Tumor Involving the Entire Stomach
    • Lymphadenopathy ≥ 1 cm

TNM Staging – AJCC 8

  • TNM
  T N M
1 1a: Mucosa/Muscularis Mucosae
1b: Submucosa		 1-2 LN Mets
2 Muscularis Propria 3-6 LN
3 Subserosa 3a: 7-15 LN
3b: ≥ 16 LN
4 4a: Serosa
4b: Adjacent Structures
    • “Early”: T1, Regardless of N
  • Stage
  T N M
I A T1 N0 M0
B T1 N1 M0
T2 N0 M0
II A T1 N2 M0
T2 N1 M0
T3 N0 M0
B T1 N3a M0
T2 N2 M0
T4a N0 M0
III A T2 N3a M0
T3 N2 M0
T4a N1-2 M0
T4b N0 M0
B T1-2 N3b M0
T3-4a N3a M0
T4b N1 M0
C T4b N3a M0
T3-4b N3b M0
IV   Any T Any N M1

Gastric Adenocarcinoma – Treatment

Endoscopic Mucosal Resection

  • Requirements:
    • ≤ 2.0 cm without Ulceration
    • Well-Moderate Differentiation
    • T1
    • No Vascular or Lymphatic Invasion
  • If Margins Positive: Surgical Resection
    • May Consider Repeat Endoscopic Resection if Only the Lateral Margins are Positive

Surgical Resection

  • Start with Diagnostic Laparoscopy to Evaluate Resectability
    • Can Skip if T1a
  • Unresectable:
    • Periaortic or Mediastinal LN
    • Distant Metastases
    • Peritoneal Involvement
    • Invasion of Vascular Structures (Not Splenic)
  • Resection:
    • Approach:
      • Proximal Tumor: Total Gastrectomy
        • Reconstruction: Roux-en-Y
        • *Proximal Gastrectomy with Pyloroplasty Has High Risk of Alkaline Reflux Esophagitis
      • Distal Tumor: Distal Gastrectomy
        • Reconstruction: Roux-en-Y or Billroth II (Avoids Outlet Obstruction if Recurs)
    • Margins: 4-6 cm
    • Residual Disease Mn
      • R0 – No Residual Disease
      • R1 – Microscopic Residual Disease
      • R2 – Gross Residual Disease
  • Lymphadenectomy:
    • Extent: Mn
      • D1 – Perigastric Nodes (Stations 1-6)
      • D2 – Celiac Axis (Stations 1-11)
        • Possible Include 12a
        • Generally Recommended (Debated)
      • D3 – Celiac & Para-Aortic (Stations 1-16)
        • No Survival Benefit
    • LN Requirements: ≥ 15 LN for Accurate Staging

Chemotherapy

  • Best Regimen Not Established
  • Indications:
    • Neoadjuvant: ≥ T2 or N1
    • Adjuvant: ≥ T3 or N1

Palliative Treatment

  • Pain: Multimodal Analgesia & Consider XRT
  • Obstruction:
    • Proximal: Stent
    • Distal: Venting Gastrostomy, Gastrojejunostomy or Gastrectomy
  • Bleeding: Endoscopy, Angioembolization or XRT

Roux-en-Y 2

Billroth 2 2

Lymph Node Stations 3

Mnemonics

Extent of Dissection

  • R-Residual
  • D-noDes

References

  1. Roshni S, Anoop T, Preethi T, Shubanshu G, Lijeesh A. Gastric adenocarcinoma with prostatic metastasis. J Gastric Cancer. 2014 Jun;14(2):135-7. (License: CC BY-NC-3.0)
  2. Terrone DG, Lepanto L, Billiard JS, Olivié D, Murphy-Lavallée J, Vandenbroucke F, Tang A. A primer to common major gastrointestinal post-surgical anatomy on CT-a pictorial review. Insights Imaging. 2011 Dec;2(6):631-638. (License: CC BY-2.0)
  3. Dikken JL, van Sandick JW, Maurits Swellengrebel HA, Lind PA, Putter H, Jansen EP, Boot H, van Grieken NC, van de Velde CJ, Verheij M, Cats A. Neo-adjuvant chemotherapy followed by surgery and chemotherapy or by surgery and chemoradiotherapy for patients with resectable gastric cancer (CRITICS). BMC Cancer. 2011 Aug 2;11:329. (License: CC BY-2.0)